From 39a3b948e525fe2b22b90e07df323ab77f6a81f6 Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Fri, 19 Jan 2024 21:26:16 -0500
Subject: keep track of focused widget

---
 focus.go             | 33 +++++++++++++++++++++++++++++++++
 gui/widget/widget.go | 44 ++++++++++++++++++++++----------------------
 main.go              | 24 +++++++++++++++++++++++-
 3 files changed, 78 insertions(+), 23 deletions(-)
 create mode 100644 focus.go

diff --git a/focus.go b/focus.go
new file mode 100644
index 0000000..e6de390
--- /dev/null
+++ b/focus.go
@@ -0,0 +1,33 @@
+package main
+
+type Focus struct {
+	widgets []chan bool
+	i       int // index of focused widget
+}
+
+func NewFocus(nWidgets int) Focus {
+	f := Focus{make([]chan bool, nWidgets), 0}
+	for i := range f.widgets {
+		f.widgets[i] = make(chan bool)
+	}
+	return f
+}
+
+func (f *Focus) Next() {
+	f.widgets[f.i] <- false
+	f.i = (f.i + 1) % len(f.widgets)
+	f.widgets[f.i] <- true
+}
+
+func (f *Focus) Prev() {
+	f.widgets[f.i] <- false
+	f.i = abs(f.i-1) % len(f.widgets)
+	f.widgets[f.i] <- true
+}
+
+func abs(n int) int {
+	if n < 0 {
+		return -n
+	}
+	return n
+}
diff --git a/gui/widget/widget.go b/gui/widget/widget.go
index 216b146..94d1915 100644
--- a/gui/widget/widget.go
+++ b/gui/widget/widget.go
@@ -28,7 +28,7 @@ func Label(text string, r image.Rectangle, env gui.Env) {
 	close(env.Draw())
 }
 
-func Input(val chan<- uint, r image.Rectangle, env gui.Env) {
+func Input(val chan<- uint, r image.Rectangle, focusChan <-chan bool, env gui.Env) {
 	redraw := func(text []byte) func(draw.Image) image.Rectangle {
 		return func(drw draw.Image) image.Rectangle {
 			drawText(text, drw, r)
@@ -40,27 +40,27 @@ func Input(val chan<- uint, r image.Rectangle, env gui.Env) {
 
 	env.Draw() <- redraw(text)
 
-	for event := range env.Events() {
-		switch event := event.(type) {
-		case win.WiFocus:
-			if event.Focused {
-				env.Draw() <- redraw(text)
-			}
-		case win.MoDown:
-			if event.Point.In(r) {
-				focus = true
-			}
-		case win.KbType:
-			if focus && isDigit(event.Rune) {
-				text = fmt.Appendf(text, "%c", event.Rune)
-				env.Draw() <- redraw(text)
-				val <- atoi(text)
-			}
-		case win.KbDown:
-			if focus && event.Key == win.KeyBackspace && len(text) > 0 {
-				text = text[:len(text)-1]
-				env.Draw() <- redraw(text)
-				val <- atoi(text)
+	for {
+		select {
+		case focus = <-focusChan:
+		case event := <-env.Events():
+			switch event := event.(type) {
+			case win.WiFocus:
+				if event.Focused {
+					env.Draw() <- redraw(text)
+				}
+			case win.KbType:
+				if focus && isDigit(event.Rune) {
+					text = fmt.Appendf(text, "%c", event.Rune)
+					env.Draw() <- redraw(text)
+					val <- atoi(text)
+				}
+			case win.KbDown:
+				if focus && event.Key == win.KeyBackspace && len(text) > 0 {
+					text = text[:len(text)-1]
+					env.Draw() <- redraw(text)
+					val <- atoi(text)
+				}
 			}
 		}
 	}
diff --git a/main.go b/main.go
index a173fd4..0161a26 100644
--- a/main.go
+++ b/main.go
@@ -20,6 +20,7 @@ func run() {
 	var (
 		displacementChan = make(chan uint)
 		output           = make(chan uint)
+		focus            = NewFocus(2)
 
 		displacement uint = 0
 	)
@@ -29,6 +30,7 @@ func run() {
 	go widget.Input(
 		displacementChan,
 		r,
+		focus.widgets[0],
 		mux.MakeEnv(),
 	)
 	r = image.Rect(
@@ -39,6 +41,19 @@ func run() {
 	)
 	go widget.Label("cc", r, mux.MakeEnv())
 
+	r = image.Rect(
+		r.Max.X+pad,
+		r.Min.Y,
+		r.Max.X+pad+widget.TextWidth(6),
+		r.Max.Y,
+	)
+	go widget.Input(
+		displacementChan,
+		r,
+		focus.widgets[1],
+		mux.MakeEnv(),
+	)
+
 	r = image.Rect(
 		pad,
 		r.Max.Y+pad,
@@ -47,6 +62,8 @@ func run() {
 	)
 	go widget.Output(output, r, mux.MakeEnv())
 
+	focus.widgets[focus.i] <- true
+
 Loop:
 	for {
 		select {
@@ -60,8 +77,13 @@ Loop:
 			case win.WiClose:
 				break Loop
 			case win.KbType:
-				if event.Rune == 'q' {
+				switch event.Rune {
+				case 'q':
 					break Loop
+				case 'j', 'l':
+					focus.Next()
+				case 'k', 'h':
+					focus.Prev()
 				}
 			}
 		}
-- 
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